Battery unit

Abstract

To protect a battery cell, housed in a battery case, from frontal collision and side collision.SOLUTION: A battery unit is disposed under a floor panel of a vehicle, with a battery cell housed in a battery case. The battery case has; a pair of first frames extending in parallel to a first direction which is one of a front-to-rear direction and a right-to-left direction; and a pair of second frames extending in parallel to a second direction which is the other one of the above-mentioned directions. The battery case is assembled in a square-frame shape that surrounds the battery cell. The first frame includes a first contact face which faces in the second direction so as to be opposed to the second frame. The second frame includes a second contact face which faces in the first direction so as to be opposed to the first frame. A first connection part of the first frame to the second frame is provided with a staircase-like first step part which defines a first space that houses at least part of a second connection part of the second frame to the first frame. At least part of the first contact face is provided on the first step part.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a battery unit that is disposed below a floor panel of a vehicle with battery cells housed in a battery case. [Background technology]

[0002] This type of battery unit is disclosed, for example, in Patent Document 1. The battery unit disclosed in Patent Document 1 includes a pair of first and second vertical frames each having a hollow cross-section, and a pair of first and second horizontal frames each having a hollow cross-section connected to both ends of the first and second vertical frames via corner brackets. The corner brackets have insertion portions that are inserted into the hollow portions of the vertical and horizontal frames, and attachment portions to the vehicle body.

[0003] In the battery unit disclosed in Patent Document 1, by interposing corner brackets between the ends of the vertical frame and the horizontal frame, impact forces can be distributed across the entire frame regardless of the direction of the impact load, whether vertical or horizontal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-97851 Summary of the Invention [Problem to be solved by the invention]

[0005] In the battery unit disclosed in Patent Document 1, although corner brackets are interposed between the ends of the vertical frame and the horizontal frame, the configuration is basically simply such that the ends of the vertical frame and the horizontal frame are butted together.

[0006] In the battery unit disclosed in Patent Document 1, if a frontal collision occurs with the vehicle, the collision load cannot be sufficiently transmitted from the horizontal frame (extending in the left-right direction) to the vertical frame (extending in the front-to-rear direction), and conversely, if a side collision occurs with the vehicle, the collision load cannot be sufficiently transmitted from the vertical frame to the horizontal frame.

[0007] The battery unit disclosed in Patent Document 1 cannot adequately protect the battery cells housed in the battery case in either a frontal collision or a side collision of the vehicle.

[0008] An object of the present disclosure is to protect battery cells housed in a battery case in a battery unit disposed below a floor panel of a vehicle from both front and side collisions. [Means for solving the problem]

[0009] The battery unit of the present disclosure is a battery unit that is arranged below a floor panel of a vehicle with battery cells housed in a battery case, and the battery case has a pair of first frames that extend parallel to a first direction, which is one of the front-rear direction and the left-right direction, and a pair of second frames that extend parallel to a second direction, which is the other of the front-rear direction and the left-right direction, and the battery case is combined in a rectangular frame shape so that the first frames and the second frames surround the battery cells, and the first frames include a first contact surface that faces the second direction so as to face the second frame, and the second frame includes a second contact surface that faces the first direction so as to face the first frame, and a first connection portion of the first frame to the second frame is provided with a stepped first step portion that forms a first space that accommodates at least a portion of the second connection portion of the second frame to the first frame, and at least a portion of the first contact surface is provided in the first step portion.

[0010] Assume that the first direction is the left-right direction and the second direction is the front-to-rear direction. When a vehicle experiences a frontal collision, the collision load is first applied to the first frame and then transferred to the second frame via the first contact surface of the first frame. On the other hand, when a vehicle experiences a side collision, the collision load is first applied to the second frame and then transferred to the first frame via the second contact surface of the second frame.

[0011] Conversely, if we assume that the first direction is the front-to-back direction and the second direction is the left-to-right direction, the first frame (first contact surface) and the second frame (second contact surface) function in reverse, and the same results are obtained.

[0012] In this way, regardless of whether a frontal collision or a side collision occurs to the vehicle, the collision load can be supported by both the first frame and the second frame.

[0013] In particular, the first connection portion of the first frame is provided with a staircase-like first step portion that forms a first space. The first space of the first frame accommodates at least a portion of the second connection portion of the second frame. At least a portion of the first contact surface of the first frame is provided on the first step portion.

[0014] This makes it easier for the first contact surface of the first frame to face the second frame, making it easier for the collision load applied to the first frame to be transmitted to the second frame via the first contact surface.

[0015] As described above, in a battery unit disposed below a floor panel of a vehicle, the battery cells housed in the battery case can be protected from both frontal and side collisions.

[0016] In one embodiment, the second connection portion is provided with a stepped second step portion that forms a second space that accommodates at least a portion of the first connection portion, at least a portion of the second contact surface is provided on the second step portion, and the first step portion and the second step portion are engaged with each other.

[0017] The second contact surface of the second frame is more likely to face the first frame. A collision load applied to the second frame is more likely to be transmitted to the first frame via the second contact surface. Furthermore, by engaging the first step portion of the first frame with the second step portion of the second frame, assembly of the first frame and the second frame is easier.

[0018] In one embodiment, the first step portion is formed in a staircase shape when viewed in the up-down direction.

[0019] In one embodiment, the first step portion is formed in a staircase shape when viewed in the second direction.

[0020] In one embodiment, the second step portion is formed in a staircase shape when viewed in the up-down direction.

[0021] In one embodiment, the second step portion is formed in a staircase shape when viewed in the first direction.

[0022] In one embodiment, the battery case has a pair of horizontal frames that are one of the first frame and the second frame and extend parallel in the left-right direction, and a pair of vertical frames that are the other of the first frame and the second frame and extend parallel in the front-to-rear direction, the horizontal frame includes a horizontal frame side contact surface that is one of the first contact surface and the second contact surface, the vehicle forms a vehicle body together with the floor panel and has a pair of front side frames that extend forward away from the front of the floor panel in the left-to-right direction, the horizontal frame side contact surface of the horizontal frame located on the front side faces rearward to face the vertical frame and is positioned to overlap in the up-down direction with the rear end of the front side frame.

[0023] In the event of a frontal collision, the collision load is first applied to the front side frames, then transmitted from the rear ends of the front side frames to the front horizontal frames, and then transmitted to the vertical frames via the horizontal frame contact surfaces of the front horizontal frames. The horizontal frame contact surfaces of the front horizontal frames are positioned so as to overlap the rear ends of the front side frames in the vertical direction. This allows the collision load from a frontal collision to be transmitted smoothly in the following order: front side frames, front horizontal frames, and vertical frames.

[0024] In one embodiment, the battery case has a pair of vertical frames that are one of the first frame and the second frame and extend parallel to the fore-and-aft direction, and a pair of horizontal frames that are the other of the first frame and the second frame and extend parallel to the left-and-right direction, the vertical frames include a vertical frame side contact surface that is one of the first frame side contact surface and the second frame side contact surface, the vehicle forms a vehicle body together with the floor panel and has a pair of side sills that extend in the fore-and-aft direction along both left-and-right edge portions of the floor panel, the vertical frames are fixed to the side sills by fasteners, the vertical frame side contact surfaces of the vertical frames face in the left-and-right direction so as to face the horizontal frames and are positioned so as to overlap with the fasteners in the up-and-down direction.

[0025] In the event of a side collision, the collision load is first applied to the side sill, then transmitted to the vertical frame via the fasteners (between the side sill and the vertical frame), and then transmitted to the horizontal frame via the vertical frame contact surface of the vertical frame. The vertical frame contact surface of the vertical frame is positioned so as to overlap the fasteners (between the side sill and the vertical frame) in the vertical direction. This allows the collision load from a side collision to be transmitted smoothly in the following order: side sill, fasteners, vertical frame, and horizontal frame. [Effects of the Invention]

[0026] According to the present disclosure, in a battery unit disposed below a floor panel of a vehicle, battery cells housed in a battery case can be protected from both frontal and side collisions. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is a top view showing the structure of the vehicle body of a vehicle according to a first embodiment. [Figure 2] FIG. 2 is a perspective view showing the structure of the vehicle body of the vehicle according to the first embodiment. [Figure 3] FIG. 3 shows the battery unit according to the first embodiment. [Figure 4] FIG. 4 is a top view showing details of the connection points between the vertical frames and the horizontal frames according to the first embodiment. [Figure 5] FIG. 5 shows the positional relationship between the lateral frame and the front side frame according to the first embodiment. [Figure 6] FIG. 6 shows the positional relationship between the vertical frame and the side sill according to the first embodiment. [Figure 7] FIG. 7 is a top view showing details of the connection points between the vertical frame and the horizontal frame according to the second embodiment. [Figure 8] FIG. 8 is a perspective view showing in detail the connection points between the vertical frame and the horizontal frame according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present disclosure, its applications, or its uses.

[0029] First Embodiment The battery unit 30 of vehicle A according to the first embodiment will be described. In the following description, the front-rear direction, left-right direction, and up-down direction are based on vehicle A. In each drawing, these directions are indicated by arrows. The front-rear direction is the direction of travel of vehicle A. The front-rear direction is an example of the second direction in this application, and is indicated by X. The left-right direction is the width direction of vehicle A. The left-right direction is an example of the first direction in this application, and is indicated by Y. The up-down direction is the height direction of vehicle A, and is indicated by Z.

[0030] (Body structure) FIG. 1 shows a top view of the structure of a body 1 of vehicle A. FIG. 2 shows a perspective view of the structure of the body 1 of vehicle A as seen from the direction of arrow II in FIG. 1. As shown in FIG. 1, vehicle A has, as components constituting the body 1, a bumper beam 2, a shroud upper member 3, a pair of apron members 4, a pair of front side frames 5, a pair of side sills 6, a dash panel 7, a floor panel 8, and a rear side frame 9. Vehicle A has a torque box 10, a suspension housing 11, and a crash can 12. Vehicle A has a battery unit 30.

[0031] Vehicle A is an electric vehicle, and is driven by a motor. Although not shown, the motor is mounted in a front space 1a provided at the front of the vehicle body 1. A passenger compartment 1b is formed in the middle of the vehicle body 1. A floor panel 8 is provided in the middle of the vehicle body 1. The floor panel 8 is substantially rectangular when viewed vertically, and extends in the front-to-rear and left-to-right directions. The floor panel 8 forms the floor surface of the passenger compartment 1b.

[0032] Vehicle A is equipped with a battery unit 30. The battery unit 30 is a power source that drives a motor for propelling vehicle A. As shown by the dashed line in FIG. 1 , the battery unit 30 is disposed below the floor panel 8 of vehicle A so as to extend along the floor panel 8.

[0033] The battery unit 30 has a rectangular appearance when viewed from above, which is substantially the same as the floor panel 8. The battery unit 30 will be described later.

[0034] As shown in Fig. 2, the front space 1a and the passenger compartment 1b are separated by a dash panel 7. The dash panel 7 extends in the vertical and horizontal directions.

[0035] A pair of side sills 6 are provided on both the left and right sides of the middle portion of the vehicle body 1. The side sills 6 are made of pillar-shaped members and have excellent strength and rigidity. The pair of side sills 6 extend parallel to each other in the front-rear direction along the edge portions 8a on both left and right sides of the floor panel 8. The pair of side sills 6, together with the floor panel 8, constitute the vehicle body 1.

[0036] A pair of rear side frames 9 are connected to the rear ends of the pair of side sills 6. The pair of rear side frames 9 extend rearward. A rear floor panel 9a, which is continuous with the floor panel 8, is provided between the pair of rear side frames 9.

[0037] As shown in Figures 1 and 2, a pair of front side frames 5 extend forward, spaced apart in the left-right direction, from in front of the floor panel 8. The pair of front side frames 5, together with the floor panel 8, form the vehicle body 1. When viewed in the vertical direction, the pair of front side frames 5 are slightly inclined so that they widen in the left-right direction as they move forward. The front side frames 5 are made up of columnar members with a rectangular cross section.

[0038] The front side frame 5 is joined to the front end of the floor panel 8 and the torque box 10 .

[0039] A suspension housing 11 is provided in front of each of the left and right ends of the dash panel 7. The lower end of the suspension housing 11 is connected to the front side frame 5. The upper end of the suspension housing 11 is connected to the apron member 4.

[0040] The apron members 4 extend forward from the outside of the suspension housing 11. The apron members 4 are curved so that they turn inward in the left-right direction as they extend forward. The front ends of the pair of apron members 4 are connected by a shroud upper member 3 that extends in the left-right direction.

[0041] A bumper beam 2 extending in the left-right direction is disposed below and forward of the shroud upper member 3. Front ends of the front side frames 5 are connected to both left-right ends of the bumper beam 2 via crash cans 12.

[0042] (battery unit) 3 shows a battery unit 30 according to the first embodiment. The battery unit 30 has a plurality of battery cells 31 and a battery case 32. The plurality of battery cells 31 are housed in the battery case 32. The battery unit 30, with the battery cells 31 housed in the battery case 32, is disposed below the floor panel 8 of the vehicle A.

[0043] The battery cells 31 are composed of lithium ion batteries or the like. All of the battery cells 31 are electrically connected and can output a predetermined high voltage. The battery cells 31 are formed in a rectangular block shape (cuboid shape) in consideration of loading efficiency into the battery case 32. In this example, 12 battery cells 31 are arranged inside the battery case 32 so that four are arranged in the left-right direction and three are arranged in the front-rear direction and are closely spaced.

[0044] The battery case 32 has a pair of vertical frames 40, a pair of horizontal frames 50, and a base member 60. The vertical frames 40 are an example of a second frame, and the horizontal frames 50 are an example of a first frame.

[0045] The pair of vertical frames 40 are spaced apart in the left-right direction and extend parallel to the front-rear direction. The pair of horizontal frames 50 are spaced apart in the front-rear direction and extend parallel to the front-rear direction. The battery case 32 is combined in the shape of a square frame when viewed in the vertical direction, so that the horizontal frames 50 and the vertical frames 40 surround the battery cells 31. In detail, the battery case 32 is formed in the shape of a rectangular frame with its long sides in the front-rear direction and its short sides in the left-right direction.

[0046] Hereinafter, the side toward the inside of the battery case 32 in the front-to-back direction (left-to-right direction) (the side where the battery cells 31 are arranged) may be referred to as the inner side in the front-to-back direction (left-to-right direction), and the side toward the outside of the battery case 32 in the front-to-back direction (left-to-right direction) (the side where the battery cells 31 are not arranged) may be referred to as the outer side in the front-to-back direction (left-to-right direction).

[0047] The vertical frame 40 is made of square pipes. The vertical frame 40 has an inverted L-shaped cross section. A flange portion 40a that protrudes outward in the left-right direction is integrally formed on the upper part of the vertical frame 40. Fixing holes 40b are formed in multiple locations on the flange portion 40a of the vertical frame 40 that are spaced apart in the front-to-rear direction (longitudinal direction) (see FIG. 4). The fixing holes 40b penetrate the flange portion 40a in the up-down direction. As will be described in detail later, fixing devices 70 for fixing the vertical frame 40 to the side sill 6 are passed through the fixing holes 40b.

[0048] The horizontal frame 50 is made of a square pipe and has a rectangular cross section. The vertical frame 40 and the horizontal frame 50 are formed by extruding aluminum, for example.

[0049] The base material 60 is a plate material that forms the bottom surface of the battery case 32. The base material 60 is arranged so as to cover from below the lower parts of the vertical frames 40, the lower parts of the horizontal frames 50, and the space partitioned by the vertical frames 40 and the horizontal frames 50. Although not shown, a lid material that covers the upper part of the battery case 32 may be provided.

[0050] (Connection between vertical and horizontal frames) 4 is a top view showing in detail the connection points between the vertical frame 40 and the horizontal frame 50. FIG. 4 shows region IV in FIG.

[0051] A vertical frame side connection portion 41 of the vertical frame 40 to the horizontal frame 50 is provided with a stepped vertical frame side step portion 42. The vertical frame side connection portion 41 is an example of a second connection portion. The vertical frame side connection portion 41 is a connection point of the vertical frame 40 to the horizontal frame 50 (see the two-dot chain line in FIG. 4). The vertical frame side step portion 42 is an example of a second step portion. The vertical frame side step portion 42 is formed in a stepped shape when viewed in the up-down direction.

[0052] Specifically, the vertical frame side step portion 42 includes a vertical protrusion 42a. The vertical protrusion 42a extends outward in the front-rear direction and in the up-down direction at the outer end portion in the front-rear direction and at the outer portion in the left-right direction of the vertical frame 40. A vertical frame side space 43, where the vertical protrusion 42a is not present, is formed at the outer end portion in the front-rear direction and at the inner portion in the left-right direction of the vertical frame 40. The vertical frame side space 43 is an example of a second space. The vertical frame side step portion 42 forms the vertical frame side space 43.

[0053] The vertical frame 40 includes a vertical frame side contact surface 44. The vertical frame side contact surface 44 is an example of a second contact surface. The vertical frame side contact surface 44 faces inward in the left-right direction so as to face the horizontal frame 50. At least a portion of the vertical frame side contact surface 44 is provided on the vertical frame side step portion 42. Specifically, the vertical frame side contact surface 44 is provided on a surface of the vertical protruding portion 42a of the vertical frame side step portion 42 that faces inward in the left-right direction. In this example, the entire vertical frame side contact surface 44 is provided on the vertical frame side step portion 42.

[0054] A horizontal frame side connection portion 51 of the horizontal frame 50 to the vertical frame 40 is provided with a stepped horizontal frame side step portion 52. The horizontal frame side connection portion 51 is an example of a first connection portion. The horizontal frame side connection portion 51 is a connection point of the horizontal frame 50 to the vertical frame 40 (see the two-dot chain line in FIG. 4). The horizontal frame side step portion 52 is an example of a first step portion. The horizontal frame side step portion 52 is formed in a stepped shape when viewed in the vertical direction.

[0055] Specifically, the horizontal frame-side step portion 52 includes a horizontal protrusion 52a. The horizontal protrusion 52a extends outward in the left-right direction and up-down direction at the outer end of the horizontal frame 50 in the left-right direction and at the outer portion in the front-to-rear direction. A horizontal frame-side space 53, where the horizontal protrusion 52a is not present, is formed at the outer end of the horizontal frame 50 in the left-right direction and at the inner portion in the front-to-rear direction. The horizontal frame-side space 53 is an example of a first space. The horizontal frame-side step portion 52 forms the horizontal frame-side space 53.

[0056] The vertical frame side step portion 42 of the vertical frame 40 and the horizontal frame side step portion 52 of the horizontal frame 50 are engaged with each other.

[0057] The horizontal frame 50 includes a horizontal-frame-side contact surface 54. The horizontal-frame-side contact surface 54 is an example of a first contact surface. The horizontal-frame-side contact surface 54 faces inward in the front-to-rear direction so as to face the vertical frame 40. At least a portion of the horizontal-frame-side contact surface 54 is provided on the horizontal-frame-side step portion 52. Specifically, a portion 54a of the horizontal-frame-side contact surface 54 is provided on a surface of the horizontal protrusion 52a of the horizontal-frame-side step portion 52 that faces inward in the front-to-rear direction. The other portion 54b of the horizontal-frame-side contact surface 54 is provided on a surface of a corner 55 of the horizontal-frame-side connection portion 51 that is slightly inward in the left-right direction from the horizontal-frame-side step portion 52 that faces inward in the front-to-rear direction.

[0058] The vertical frame side space 43 of the vertical frame 40 accommodates at least a part of the horizontal frame side connection portion 51 of the horizontal frame 50. Specifically, the vertical frame side space 43 of the vertical frame 40 accommodates the corner portion 55 of the horizontal frame side connection portion 51 of the horizontal frame 50.

[0059] The horizontal frame side space 53 of the horizontal frame 50 accommodates at least a part of the vertical frame side connection portion 41 of the vertical frame 40. Specifically, the horizontal frame side space 53 of the horizontal frame 50 accommodates the vertical protrusion portion 42a of the vertical frame side step portion 42 of the vertical frame side connection portion 41 of the vertical frame 40.

[0060] (Positional relationship between the horizontal frame and the front side frame) 5 is a cross-sectional view showing the positional relationship between the horizontal frame 50 and the front side frame 5, as seen from the direction of arrow V in FIG. 4. The horizontal frame-side contact surface 54 of the horizontal frame 50 located on the front side faces rearward so as to face the vertical frame 40. The horizontal frame-side contact surface 54 of the horizontal frame 50 located on the front side is positioned so as to overlap the rear end portion 5a of the front side frame 5 in the vertical direction.

[0061] (Positional relationship between vertical frame and side sill) FIG. 6 is a cross-sectional view showing the positional relationship between the vertical frame and the side sill 6 as viewed from the direction of arrow VI in FIG.

[0062] A flange portion 40a that protrudes outward in the left-right direction is integrally formed on the upper portion of the vertical frame 40. A side sill 6 is disposed above the flange portion 40a of the vertical frame 40. The flange portion 40a of the vertical frame 40 is fixed to the side sill 6. Specifically, the flange portion 40a of the vertical frame 40 is fixed to the side sill 6 by a fastener 70. The fastener 70 is passed through a fastening hole 40b formed in the flange portion 40a. The fastener 70 is, for example, a bolt.

[0063] The vertical frame side contact surfaces 44 of the vertical frames 40 face inward in the left-right direction so as to face the horizontal frames 50. The vertical frame side contact surfaces 44 of the vertical frames 40 are positioned so as to overlap the fixing fixtures 70 in the up-down direction.

[0064] (Action and effect) When a frontal collision occurs to vehicle A, the collision load due to the frontal collision (hereinafter referred to as "frontal collision load Fx") is first applied to the horizontal frame 50, and then transmitted to the vertical frame 40 via the horizontal frame side contact surface 54 of the horizontal frame 50. On the other hand, when a side collision occurs to vehicle A, the collision load due to the side collision (hereinafter referred to as "side collision load Fy") is first applied to the vertical frame 40, and then transmitted to the horizontal frame 50 via the vertical frame side contact surface 44 of the vertical frame 40.

[0065] In this way, when the vehicle A is hit by either a frontal collision or a side collision, the collision load can be supported by both the horizontal frame 50 and the vertical frame 40.

[0066] A stepped horizontal frame side step portion 52 that forms a horizontal frame side space 53 is provided at the horizontal frame side connection portion 51 of the horizontal frame 50. The horizontal frame side space 53 of the horizontal frame 50 accommodates at least a portion of the vertical frame side connection portion 41 of the vertical frame 40. In the horizontal frame 50, at least a portion of the horizontal frame side contact surface 54 is provided at the horizontal frame side step portion 52.

[0067] The horizontal frame side contact surface 54 of the horizontal frame 50 is more likely to face the vertical frame 40. The frontal collision load Fx caused by a frontal collision applied to the horizontal frame 50 is more likely to be transmitted to the vertical frame 40 via the horizontal frame side contact surface 54.

[0068] Similarly, a stepped vertical-frame-side step portion 42 that forms a vertical-frame-side space 43 is provided in the vertical-frame-side connection portion 41 of the vertical frame 40. The vertical-frame-side space 43 of the vertical frame 40 accommodates at least a portion of the horizontal-frame-side connection portion 51 of the horizontal frame 50. In the vertical frame 40, at least a portion of the vertical-frame-side contact surface 44 is provided in the vertical-frame-side step portion 42.

[0069] The vertical frame side contact surfaces 44 of the vertical frames 40 are more likely to face the horizontal frames 50. The side impact load Fy due to a side impact applied to the vertical frames 40 is more likely to be transmitted to the horizontal frames 50 via the vertical frame side contact surfaces 44.

[0070] As described above, in the battery unit 30 disposed below the floor panel 8 of the vehicle A, the battery cells 31 housed in the battery case 32 can be protected from both frontal and side collisions.

[0071] By engaging the horizontal frame side step portions 52 of the horizontal frame 50 and the vertical frame side step portions 42 of the vertical frame 40 with each other, the horizontal frame 50 and the vertical frame 40 can be easily assembled together.

[0072] When a frontal collision occurs to vehicle A, the frontal collision load Fx is first applied to the front side frame 5, then transmitted from the rear end portion 5a of the front side frame 5 to the front horizontal frame 50, and then transmitted to the vertical frame 40 via the horizontal frame-side contact surface 54 of the front horizontal frame 50. The horizontal frame-side contact surface 54 of the front horizontal frame 50 is positioned so as to overlap the rear end portion 5a of the front side frame 5 in the vertical direction.

[0073] As a result, the frontal collision load Fx due to a frontal collision can be smoothly transmitted through the front side frame 5, the front horizontal frame 50, and the vertical frame 40 in that order.

[0074] When a side collision occurs to vehicle A, the side collision load Fy is first applied to the side sill 6, then transmitted to the vertical frame 40 via the fixing device 70 (between the side sill 6 and the vertical frame 40), and then transmitted to the horizontal frame 50 via the vertical frame side contact surface 44 of the vertical frame 40. The vertical frame side contact surface 44 of the vertical frame 40 is positioned so as to overlap the fixing device 70 (between the side sill 6 and the vertical frame 40) in the up-down direction.

[0075] This allows the side impact load Fy due to a side impact to be transmitted smoothly through the side sill 6, the fixing member 70, the vertical frame 40, and the horizontal frame 50 in that order.

[0076] Second Embodiment A second embodiment will be described below. In the following description, the same components as those in the above embodiment will be denoted by the same reference numerals, and detailed description thereof will be omitted.

[0077] FIG. 7 is a top view showing details of the connection points between the vertical frame 40 and the horizontal frame 50 according to the second embodiment.

[0078] In this embodiment, similar to the first embodiment, the horizontal frame side connection portion 51 of the horizontal frame 50 to the vertical frame 40 is provided with a staircase-like horizontal frame side step portion 52. However, unlike the first embodiment, the vertical frame side connection portion 41 of the vertical frame 40 to the horizontal frame 50 is not provided with a staircase-like vertical frame side step portion 42.

[0079] The horizontal frame side space 53 of the horizontal frame 50 accommodates the entire vertical frame side connection portion 41 of the vertical frame 40.

[0080] Other configurations are the same as those of the first embodiment. According to this embodiment, the same effects as those of the first embodiment can be obtained.

[0081] <Third embodiment> A third embodiment will now be described. In the following description, the same components as those in the above embodiments will be given the same reference numerals, and detailed description will be omitted. Figure 8 is a perspective view showing the details of the connection points between the vertical frame 40 and the horizontal frame 50 according to the third embodiment.

[0082] In this embodiment, the vertical frame side step portion 42 is formed in a stepped shape when viewed in the left-right direction, and the horizontal frame side step portion 52 is formed in a stepped shape when viewed in the front-rear direction.

[0083] Other configurations are the same as those of the first embodiment. According to this embodiment, the same effects as those of the first embodiment can be obtained.

[0084] <Other embodiments> Although the present disclosure has been described above with reference to preferred embodiments, such description is not limiting, and it goes without saying that various modifications, substitutions, or combinations are possible.

[0085] In the above embodiment, the first direction is the left-right direction and the second direction is the front-rear direction, but this is not limited to this. The first direction may be the front-rear direction and the second direction may be the left-right direction. Even in this case, the same effects as in the above embodiment can be obtained.

[0086] The first direction is one of the front-rear direction and the left-right direction. The second direction is the other of the front-rear direction and the left-right direction. The horizontal frame 50 is one of the first frame and the second frame. The vertical frame 40 is the other of the first frame and the second frame. Similarly, the horizontal frame side contact surface 54 is one of the first contact surface and the second contact surface. The vertical frame side contact surface 44 is the other of the first contact surface and the second contact surface. [Industrial Applicability]

[0087] The present disclosure is applicable to battery units and is therefore extremely useful and has high industrial applicability. [Explanation of symbols]

[0088] X Anteroposterior direction (second direction) Y left / right direction (first direction) Z vertical direction Fx Front collision load (collision load) Fy Side impact load (collision load) Vehicle A 1. Body 1a Front space 1b Cabin 2 bumper beams 3 Shroud upper member 4 Apron Members 5 Front side frame 5a Rear end 6 Side sill 7 Dash Panel 8 Floor Panels 8a Edge 9 Rear side frame 9a Rear floor panel 10 Torque box 11 Suspension housing 12 Crush Can 30 Battery Unit 31 battery cells 32 Battery case 40 vertical frame (second frame) 40a flange 40b fixing hole 41 Vertical frame side connection part (second connection part) 42 Vertical frame side step (second step) 42a Vertical protrusion 43 Vertical frame side space (second space) 44 Vertical frame side contact surface (second contact surface) 50 horizontal frame (first frame) 51 Horizontal frame side connection part (first connection part) 52 Horizontal frame side step (first step) 52a Lateral protrusion 53 Horizontal frame side space (first space) 54 Horizontal frame side contact surface (first contact surface) 54a part 54b Other Departments 55 corner 60 Substrate 70 Fixtures

Claims

1. A battery unit that is disposed under a floor panel of a vehicle with battery cells housed in a battery case, The battery case includes: a pair of first frames extending parallel to a first direction, which is one of a front-rear direction and a left-right direction; a pair of second frames extending parallel to a second direction that is the other of the front-rear direction and the left-right direction, The battery case is configured such that the first frame and the second frame are combined into a rectangular frame shape so as to surround the battery cells, the first frame includes a first contact surface facing the second frame in the second direction, the second frame includes a second contact surface facing the first direction so as to face the first frame, a first connection portion of the first frame to the second frame is provided with a stepped first step portion that forms a first space that accommodates at least a part of the second connection portion of the second frame to the first frame; At least a portion of the first contact surface is provided on the first step portion.

2. the second connection portion is provided with a stepped second step portion that forms a second space that accommodates at least a portion of the first connection portion, At least a portion of the second contact surface is provided on the second step portion, The battery unit according to claim 1 , wherein the first step portion and the second step portion are engaged with each other.

3. The battery unit according to claim 1 or 2, wherein the first step portion is formed in a staircase shape when viewed in the up-down direction.

4. The battery unit according to claim 1 or 2, wherein the first step portion is formed in a staircase shape when viewed in the second direction.

5. The battery unit according to claim 2 , wherein the second step portion is formed in a staircase shape when viewed in the up-down direction.

6. The battery unit according to claim 2 , wherein the second step portion is formed in a staircase shape when viewed in the first direction.

7. The battery case includes: a pair of horizontal frames that are one of the first frame and the second frame and extend parallel to each other in the left-right direction; a pair of vertical frames that are the other of the first frame and the second frame and extend parallel to each other in the front-rear direction, the horizontal frame includes a horizontal frame side contact surface that is one of the first contact surface and the second contact surface, The vehicle includes a pair of front side frames that form a vehicle body together with the floor panel and extend forward from a front side of the floor panel at a distance in the left-right direction, 3. The battery unit according to claim 1, wherein the horizontal frame contact surface of the horizontal frame located on the front side faces rearward to face the vertical frame and is positioned so as to overlap the rear end of the front side frame in the vertical direction.

8. The battery case includes: a pair of vertical frames that are one of the first frame and the second frame and extend parallel to each other in the front-rear direction; a pair of horizontal frames that are the other of the first frame and the second frame and extend parallel to each other in the left-right direction, the vertical frame includes a vertical frame side contact surface that is one of the first frame side contact surface and the second frame side contact surface, The vehicle includes a pair of side sills that form a vehicle body together with the floor panel and extend in a front-rear direction along both left-right edge portions of the floor panel, The vertical frame is fixed to the side sill by a fastener, The battery unit according to claim 1 or 2, wherein the vertical frame-side contact surfaces of the vertical frames face the horizontal frames in the left-right direction and are positioned so as to overlap the fixing members in the up-down direction.

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